The answer is yes and no. The hair that is outside of your scalp is considered dead, simply because there are no blood vessels, nerves or muscles. Even though our hair is dead it, can stretch up to 30% of its length, if it’s healthy, and can also absorb its own weight in water. Our hair is also remarkable by virtue of its resilience. We color, cut, wash, brush, heat, cool, pull, tug, twist and rub our hair; and if it’s in good health, still remains intact.
So if our hair is dead how can it do all of that?
The hair shaft (the part of the hair that we see outside our scalp) is made up of three layers. The Cuticle is the protective exterior that consists of overlapping layers that look similar to the scales of a fish. When our hair is healthy these layers are closed down smooth giving us that shiny silky appearance. The Cortex is the middle layer that gives our hair the bulk or thickness and also contains the melanin (color) of your hair. Lastly, the medulla is a thin core of transparent cells. In very fine hair the medulla may not even be present. The primary building block of our hair is keratin (a type of protein) and it has cells similar to the cells that make up our skin. The keratin, along with several other nutrients, gives our hair strength and gives us the appearance of what we call “Healthy Hair”. Even with all of these working parts, your hair is still considered dead.
The part of your hair that is alive is the hair follicle because it has its own blood supply, nerve endings and muscles. Each strand of hair grows from its own individual follicle from the Papilla (the bud of the hair). The body provides nutrients to the follicle along with blood and oxygen so that the hair is able to grow. The nerves are what causes you to be able to feel when someone pulls your hair or it blows in the wind and you feel the motion. The muscles contracting around the follicle is what causes “goose bumps” that make our hair stand up. Your hair also grows in stages. There is a growing phase (this can last several months to years), there is a resting phase (no growth is going on), and lastly there is a shedding phase (this is why we lose our hair). Each follicle is on its own cycle and that is why we are constantly loosing and growing hair.
So take care of your scalp, keep your body healthy and you will reap the benefits of healthy hair from the inside out.